Q. A paraboloidal antenna has an aperture ef?ciency of 0.6 and a diameter D = 100λ at 6 GHz. Illumination by the feed is such that the beamwidths of the principal-plane secondary patterns are equal. Determine the antenna's power gain and beamwidth. (Note that the radiation pattern of the feed is called the primary pattern, whereas that of the overall antenna is the secondary pattern.)